The present invention relates to a wire connecting structure and a method of connecting a terminal with a covered wire having core lines covered with an insulating cover, the wire connecting structure being obtained by mounting the covered wire on the terminal and sequentially fusing the insulating cover by ultrasonic energy under pressure, thereby electrically connecting the terminal with the core lines of the wire.
Japanese Unexamined Patent Publication (Kokai) No. 7-70345 discloses a conventional connecting structure where a covered wire and a terminal are interposed between a first member and a second member. Both of the first and second members are made of plastic materials which are soluble in each other by ultrasonic oscillation.
In this connecting structure, the first member is provided with a plurality of grooves, while the second member is provided with a plurality of projections for respective engagement with the grooves. In order to connect the terminal with the covered wire, the terminal is firstly accommodated in one of the grooves and the wire is mounted on a wire mounting surface of the terminal in succession. Then, the second member is laid on the first member so that the projections engage in the grooves, respectively. Next, under such a condition, the first and second members are vibrated by the ultrasonic waves while exerting a pressure on both members. Consequently, owing to this ultrasonic oscillation, the insulating cover is fused, so that the exposed core lines come into electrical contact with the terminal.
While, in the above-mentioned connecting structure, the first member is welded to the second member by the ultrasonic oscillation, simultaneously. Therefore, even if a poor connection between the terminal and the wire is caused, it is impossible for an operator to ascertain a situation of the poor connection while opening the structure. Further, such an integrated connecting structure does not allow the operator to separate both members from each other, exchange the terminal for another one, reconnect the terminal with the wire again and so on.